Piston motor



Filed Feb. 9,' 1951 2 Sheets-Sheet 1 W. ZWICK PISTON MOTOR July 4, 1933.

Filed Feb. 9, 1951 2 Sheets-Sheet 2 Patented July 4, 1933 n UNITED STATES WALTER ZWIGK, OF BERLIN-'WESTEND,'GERMANY P Isron Moron Application filed February 9, 1931, Serial No. 514,591, and in Germany February 10, 1930.

This invention relates to a piston motor, preferably an internal combustion motor. All motors or engines of this type operate in this way that the number of thev strokes of the piston or pistons is in a uniform relation to the number of the revolutions ofthe motor or engine shaft so that a `change of the turning moment transmitted from said shaft to the machine driven'by the motor with uniform performance can be brought about only by means of lan intermittent gearing.

The object of therpresent invention is to render the use of such a gearing superfluous. To attain this object the motor is so designed that with uniform performance. the turning can be changed corresponding to the requirement, preferably automatically. The invention is carried out in this way that the number of strokes of the piston or pistons is made independent ofthe ynumber of revolutions `of the motor shaft, preferably in this manner that the pistons areA being coupled with this shaft only duringv a certain time, whereas during that time in which the pistons are not coupled with the motor shaft the work done by them is accumulated and is afterwards, when these members have again been coupled, transmitted; to the said shaft in order tobe utilized. .The shorter the time is in which the pistons and the shaft are coupled with one another, the shorter is,

however, also the path during which energy is transmitted to the motor shaft; in` other words: the number of revolutions of the motor shaft is reduced for -a certain short time with the aid of a coupling provided for the piston or pistons, the turning moment being at the'sametime correspondingly increased. The adjustment is effectedby hand or automatically by a governor of any suitable den sign, for-instance by a torsion dynamometer,

a centrifugal governor or the like.

The invention is illustrated diagrammatically and by wayof example on the accompanying drawings on which Figure 111s a section through a motor designed according to lthis invention, the section lying trans-` versely to the motor shaft; Figure'2 is a similar view rela-ting to amodiiicatron ;V Figl -ure 3 is a. vertical section in the plane 3-3 of Fig. 2;- Figures 4 and 5 show details relating to Fig. 3 and being drawn to an enlarged scale; Figure G is a performance diagram disclosing the manner of operation of the motor; and Figure 7 is a section through still another constructional form of the motor, all as fully described hereinafter.

Referring to Fig. 1, 2 denotes the cylinder of the motor which is circular and stationary;

within this cylinder circulate two pairsof pressed into it by a blower 10; it enters iirst into a channel 11 and passes from thisv channel through apertures 12 into the cylinder.- The apertures, 13 are the exhaust apertures. @ne of the spokes is provided with a pivot'14supporting a'bell-crank lever 16, one arm of which contacts with. a friction 'roller 15, whereas* the 'other arm carries a roll 17 contacting with a cam disk 18 supportedloosely upon the shaft 9. The roll 15 is located between the lever 16 and a friction roll 19 aiiixed to the shaft 9. The cam disk 18 is engaged'by a guide rod 20, the other end ofv which is jointed to a double lever 21 which is supported on a pivot 22 secured to afbracl-et 23; the other armof this lever en'- gages the sliding member 24 of a centrifugal governor 25. The axle 26 of this governor is provided with a bevel-wheel 28, and also a pulley 29 is affixed to said. axle. The pulley 29 is driven by means of a pulley 31 and a belt 30; the pulley 31 is aiiixed to the shaft 9.

v The cylinder 2 is divided by partition walls 32 and 33 into two chambers-0f semicircular shape, and in each thereof one of the two pairs of pistons is housed.

hel operation of this motor is as follows l/Vhen the parts are in the position shown in Fig. 1 va compressed. gas-air-mixture is contained between the partition Wall 32 and the piston 4, aswell as between the partition `blower 10 also in knoi. manner 4.from the rotating shaft. resents of course, the'output o-f only one piston; they performances `of the four pistons wall 33 and the piston 3a.; the mixture is ignited in known manner and the star consisting of the spokes 7, the connecting members 5 and 6, and the piston commencesto rotate in clockwise direction. mmediately prior thereto the combustion gases that were present in the space between rthe wall 33 and the piston 4a, as well as in the space between the wall 32 the piston out through the apertures 13, and said spaces had then been scavei d by fed by the l.li-ereupon a fresh charge (gas-air-minture) had been pumped into said spaces. At the stroke new following the fr si mixture is ceii'ipressed again in the usual manner and atthe end of proceeds in clockwise direction thismixture is ignited and exploded, so that the piston star now runs in the opposite direction. This star nieves, therefore uninterruptedly to and fro as long as always the same amount of the gas-air-mixture isk supplied. `mitted by the free-wheel coupling 15, 16 as This motion of the star is transsoon as the pistons-circulate with the same number of revolutions as does the shaft 9.

'The engagement' of the coupling members takes place free of shocks, and the rotatory motion is transmitted to the disk19.' As long the roll -17 is ruiming upon the Yhigher part of the cani disk 18, the frictionroll 15 lis held'clampe'd fast between one arm of the lever 16 and lthe disk 19, and this disk is then taken round together with the but as soon as the roll S17-gets into the deepened "part ofthe cam disk 18,'thefriction roll 15 Nis vreleased and the pistonstar'runs without load, that is to say, is no more coupled with the motor shaft. The adjustment of ythe cam disk 18 is effected by turning it about its axis 9 by means of the 'centrifugal governor 25. As this governor is coupled with and driven bythe shaft 9, it runs with the same speed as the mentioned shaft. The quicker the shaft 9 is running, the more the centrifugal regulator is raised and the disk 18 turned about its axis in clockwise direction and the longer will the roll 17, during one stroke of .the vpiston star bear upon the cam disk 18,

andthe longer will the star remain coupled with the shaft.

|TheV performance of the motor is determined chiefly by the stroke volumeand the number of periods of the oscillating pistons. This number is determined in turn chiefly by the mass of the pistons. lf the performance" of the motor is put down in a diagram according to Fig. 6, that performance would `be proportional'tothe diagram surface from S to A, if S represents the point of time of the explosion, and A denotes the point of time at which trie piston star is disengaged diagram rep- 3, had beendriven cover and overlap one another more or less. The performance of the motor depends, thus, upon the number of revolutions of the shaft 9; with decreasing number, the turning moment which the motor produces increases correspondingly, in that, with a small number of. revolutions, the shaft 9 when being driven byA thefpiston star turns through only a small angle, whereas the pistons continue their path without being coupled with the shaft. Thus, with a small number of revolutions of the shaft 9 a larger number of working strokes of the piston star will exert vtheir ef'iectatone revolution of the shaft thiln number of vthe working strokes acting atene with a larger number of revolutions.

revolution of the shaft 9 is determined'by the adjustment of the cam disk1'8, and this adjustment is regulated, in the example in question, by the number of revolutions of the disk 19, so that'fwhen the motor runs more quickly and the Aturning moment to be performed is, therefore, smaller, a smaller turninc' moment is automatically provided for,

that is to say, the motor is adjusted for a smaller number of working strokes per one revolution, whereas, with a great resistance,

thus, with slowly rotating shaft, the cam disk r18 is automatically so adjusted that a-l'argc number of piston strokes takes placeat one rotation of the shaft, in consequence whereof 'the turning moment is correspondingly increased. l y

lt is, of course, also possible to adjust'the cam disk 18 automatically, the centrifugal governor being then dispensed with, but generalythe automatic adjustment will be prefera le. 1

'The constructional formV shown in Figs. 2V K 'an d 3 differs from that firstdescribed chiefiy j ternally slotted andthis slot Yis closed by the disk 39. The revolutions ofthe cylinder are transmitted to the sha-ft 40 (Fig. The disk 39 is connected with a crank 42 by means of a rod 4l, and the crank pin 43 is supported in the' cylinder body. The crank pin is connected with two cog-wheels l44 which mesh withA cog-wlieels 45. VOne `of these y wheels runs freely upon a shaft 46, vwhereas the other runs freely upon a hollow shaft 47. The two cog-wheels 45 yare firmly connected by means ofpins with camdisks 48 by means of which the valves 49 are controlled in the mannerknown with internal combustionmachines. Thus, the four spaces p1, p2, p3, p4 formed in the cylinder 34 are alternately supplied with the gas-air mixture; this is then CIJ Q.. qu

ra friction clutch as in the first case.

ignited and exploded and the pistons 37 and 38 are moved to and fro together with the disk 39. The shafts 40 vand 46 are connected with each other by means of the Itorsion dynamometer 62-68. rlhis coupling device is Y manner with a pinion driven by an' electro- I motor oi' the like. rlhis driving means have not been shown.

As long as the cylinder 34 being at a standstill, the pistons are reciprocated in the manner stated by ignitions taking place at the end of the strokes the energy they generate will be accumulated more and more, that is to say, they will move quicker and quicker until a certain maximum number of oscillations lias been attained, without` any outward transmission of the energy. For effecting this transmission, i. e. to the motor shaft, a ratchet-wheel clutch is provided in lieu of The disk 39 is either made integral with the hollow shaft 47, or these two members are rigidly connected with one another; it is supported in a bearing l which, together with the bearing 52 serving for supporting the shaft 40, constitutes a part of the frame 53.

The bearing 51 is provided with ratchet teeth 54 (Fig. 4) which can be engaged by a pawl 55 attached by means of a keyy 56av to a lever 56 provided with apivot 57 for that purpose, and this lever is firmly secured to the hollow shaft 47. The solid shaft 46 arranged within said hollow shaft is firmly connected with the motor shaft 40', and at the` free end of the shaft 46 is an abutment lever 58 which can engage a smalll projection 59 of the pawl 55. As long as this pawl engages the ratchet wheel 54 the hollow shaft 47 and,.thus, also the disk 39 with the piston are prevented from turning relatively to the bearing 5l, in consequence whereof the energy developed on the one hand between the pistons 37 and 38 and on the other hand between the walls 35 and 36 acts in such a direction that'the cylinder commences to rotate. When the motion proceeds in the reverse direction the teeth of the ratchet wheel 1 54 can slide along the pawl and the pistons can, therefore, freely move back into their former position.V

The pistons act, thus, when moving in the one direction as long upon the cylinder 34 and turn it as long as the clutch members between the ratchet wheel 54 and the pawl 55 are in engagement with one another, but this engagement is broken by the abutment meml ber 58 which rotates together with the cylinder. Accordingasthe member 58'has been adjusted the disk 39 will be renderedk stadirection.

tionary, together with the pistons 37 and 38, fora shorter or longer period of time, and owing thereto the energy developed in the motor will act upon the cylinder for a shorter or longer time. As, however, the number of the strokes remains the same, there will during that timein which' the pistons are disengaged .from the frame of the motor and `can freely oscillate the developed energy be accumulated and the turning moment arising during, or at, the coupling procedure will be the stronger.

Reverting to the diagram shown in Fig. 6 I point to the feature that in the moment of the ignition a work corresponding to the surface from F to S is available. The hatched part of the diagram extending until ,A must at least be so largel as to be able to do the resistance work for the compression in the cylinder, the expelling of the burned mixture, and the sucking in.

Referring to Fig. 2 it may be assumed that the pistons are moving in counter-clock- .wise direction. In this case a part of the performance in the space p2 must be used for compressing the mixture in the cylinder p3, and then the burned mixture must be expelled and simultaneously therewith fresh vmixture must be sucked into thecylinder p4.v

As soon as the piston 37 has approached the wall 36, another combustion takesV place, so that the disk 39 now rotates in clockwise This reversal of the movement would actretarding upon the cylinder 34, but requires, in fact, onlyra small fraction of its energy of motion as large masses are connected with the cylinder. That part of the energy which the cylinder has, indeed, given ofi' is transmitted back to the piston V37 or 38 bythe compressed gases, and this energy, as well as the entire work of the compressed gases, is transformed into vis viva of the pistons 37 and 38 and the masses connected therewith.

When then the next combustion takes place,

' in the space p4, viz. when the piston 38 has approached the wall v35, then the compressed gases turn the pistons and the mass connected with them again in counter-clockwise di- The pawl 55 engages again the 34 is thererection.A

ratchet wheel 54 and the cylinder upon taken round, the energy accumulatedv in the piston being now transn'iitted to the cylinder.

The work of all four working strokes -in the four spaces 291-794' is transmitted to the cylinder in the same direction, and a part of this mechanial workis transformed in continual alternation into vis 'viva of the masses oscillating together with the piston,

a nd this vis viva is then re-transformed into 58 may also in this case be effected by lhand rw;

for the purpose of varying the turning moment, but it is as well possible to make use of an automatically acting device. With the constructional `form now described a tori f and is providedwith a pin 63 engaging a slot 64 of a lever 65; this slot is engaged also by a. pin 66A projecting forth from the cylin- Lder 34. The two pins determine the position of the lever 65. This lever is jointed 1 by means of a pin 67 to a lever 68 firmly secured to the shaft 46. When the cam is turned in counter-clockwise Adirection relatively to the cylinder 34 and, thus, also relatively tofthe pivot 66, the lever and, therefore, also the shaft 46 will be'turned and this shaft turns, in *.turn, the abutment member The extent of the turning depends upon the shape of the slot 64 which can be designed as desired.

vber 53 the period of time during which the .proaches thewall 35.

By the adjustment'of the mempistons are coupled with the' frame is eX- tended or shortened, and owing hereto the number of revolutions of the motor is decreased, simultaneously with an increase of the turning moment, or reversely. Y In order torender the manner of operation of the device still more lucid, I state furthermore what follows:

The turning moment exerted upon the cylinder 34 is, apart from constructionalY data, dependent only upon the medium pressure which thecompressed mixture exerts upon the walls and 36 during one complete revolution of the cylinder. If the pawl is lifted very early then a large part of the working diagram (Fig. 6), say from F to G, is transformed intovis viva of the pistons 37 and 38. This energy is, when the direction of motion of the pistons has been reversed7 first transformed into compression work and acts' then in the opposite direction upon the pistons 37 and 38. This work or eect is assisted by the work of the combustion stroke in vthe space p3 whereby the piston 37 is also accelerated. .This piston receives, therefore, a considerable kinetic energy when its ap- Tn the .Oiven moment the ignition in the space jp takes place, whereby lthe cylinder 34 will be accelerated and the piston V37 will be retarded. In spite of the high pressure in the moment ofthe ignition the piston 37 is not momentarily stopped, but proceeds in its movement 4to the right counter to the gas pressure, and will even aproach the wall 35 and compress further the already ignited gases, which takes in the direction place tothe lineH in the diagram (Fig. V6).

way which the piston 37 covers together with `thewall 35, the piston transmits its kinetic energycompletely to the cylinder 34.* The medium pressure during one stroke can be ascertained ,from the surface between G and H, as well as from the path which the piston 37 and the wall 35 have jointly covered. The working strokes at a slow rotation andthe high turning moments are for one revolution more numerous thanY with a quickly running motor and a low` turning moment.`

The retically the turningmoment might be infinitely large if the cylinder 34 is held fast, as,v since the pistons and the parts connected Vwith them do not give'otr" work exterior-ly, another amount of kinetic energy vis added at every working stroke. VThe pistons would thus move with higher and higher'speeds, the stroke would become longer and longer, and

the compression of the gases wouldcontinu-I ally rise.f Tf the mass of the pistons 37 and 33 is spoken of, there is then meant, of course, the entire mass connected with said pistons, as well as the momentum of inertia ofthe same.' As the motorr changes its turning The thermic efliciency becomes vcorrespondingly better. On thatV moment and its number `of revolutions continuallyl within large limits a separate change-speed gearing is not requisite. vThe motor can operate as a two-stroke cycle motor, as well as a sired.

Finally, another constructional form is shown in Fig. 7 in which actually alined cylinders instead kof the curved ones are employed; 70 and 7 'l denote these cylinders, and 72 and 73ers the pistons of the same; they Vare connected with one another lbya rod l74.

The waste gases escape throughslots 75,- and the scavenging air and the' combustible charge is introduced through slots 76. Hingedto the rod 74 at 73 is a push. rod 79 iii-which a. pawl 8l is oscillable upon a pin 30.` This four-stroke cycle motor, asidepawl is designed as a double-lever and is provid-ed at its free end with a roll 3Q running along a cam 83 designed iF-va segment and l* supported loosely by means cfa hub 8.4 upon the driven shaft 85. irmly aiiix'ed to this shaft is a. ratchet wh el 86 whichV said pawl can engage.V hns, when the pistons move to and fra, the movement is transmitted by the pawl 8l to the ratchet wheel anch-thus, to the driven shaft When the pawl isibeing moved byt intermediary of the guiderod '77, the roll 82 is being moved along the cam 33, and when it contacts witl'i the thicker portion of this cam, it is lifted out of the ratchetwheel and the piston is :uncoupled from; the driven shaft sc that it can now continue `to work in the already described manner and can cam 83 is in this case effected manually by means of a grip 87.

Wish it to be understood that I do not limit myself to the constructional forms described and shown merely by Way, of eX- ampl-e, nor to all the details shown and described in connection With said constructional forms, Many departures are possible With-' 2. Transmission means according to claim l, said means being adjustable corresponding to the conditions of rotation.

3. A transmission particularly for internal combustion motors for transmitting the movements of the pistons to the shaft comprising in combination With pistons freely movable in one stroke and a shaft, tvvo clutch members coacting with said pistons during the counter-stroke thereby coupling them With ,said shaft, one clutch member being coupled with the shaft When turning in one direction, and the other when turning in the other direction, and means adapted to positively disengage the clutch member at any desired point of the counter-stroke.

vIn testimony whereof I have affixed my si gn ature.

VALTER ZWI CK. 

